A number of electronic systems have a requirement for a high Radio Frequency (RF) power transmitter having performance over a wide instantaneous frequency bandwidth. For example, some electronic counter-measure systems employ Traveling Wave Tube Amplifier (TWTA) technology to achieve the combination of wide frequency bandwidth and high output power performance. Tube based amplifiers, however, are associated with a number of limiting disadvantages. For instance, they are relatively large in physical size, and require very high-voltage power supplies (sometimes thousands of volts).
Present solid-state wideband power amplifiers, using established gallium arsenide (GaAs) transistor technology, offer a smaller size than tube-based approaches but have significantly lower power density and are primarily limited to low to medium RF power applications (usually less than 15 W). In addition, their power density capability requires a significant level of circuit power-combining, which usually limits the obtainable RF output power level.